Telephone-exchange system.



` nien aras errar enteren ELMERR. CORWIN, OF CHICAGQ-ILLINOIS, ASSIGNOR TO MONARC'H TELEPHONE MANUFAC- TURING CO., A CORPORATION OF ILLINOIS.

TELEPHONE-EXCHANGE SYSTEM.

No. esami.

Specification of Letters Patent.

Patented May 26, 1908.

Application led October 1, 1906, Serial No. 337,029.

ratus whereby telephone exchange practice may be simplified and improved.

My invention is serviceable in connection with switch-boards of the simple or multiple type, and one feature of the invention is of particular service in connection with multiple switch-boards. i

My invention will more fully ap ear by reference to the accompanying diawing, showing its preferred embodiment as applied to multiple switch-boards, and will be pointlso ed out in the claims. y

In the drawing there are indicated two of many sub-stations, A, B, which, in this instance, are subscribers stations, eachhaving a transmitter 1, a receiver 2, a call bell 3, a switch-hook 4,'a condenser 5, and an impedance coil 6, together with suitable contacts and circuit connections whereby, when the tele hone receivers are upon their switchhoo s, the bells 3, together with the condensers 5, are bridged across thesides of the telephone lines 7, 8, and whereby, when the tele hone receivers are removed from their hoo s, the bridges including signaling bells are opened and the transmitters are thrown into conductive connection with the lines, whereby battery may be fed therethrough through the impedance coil 6, and whereby these currents may be im ressed upon the lines at the sub-stations at he transmitters or may be receivedl at the receivers. I do not Wish, however, to-be limited to the precise sub-station circuits indicated. The limbs 7, 8 of the telephone lines are, in multiple switchboard practice, multiplied to sleeve contacts or thimbles 9 and rin contacts 16, respectively, of multi le spring jacks, though the invention may lie useful in connection-with switch-boards that are not multiple switchboards, in which case but one jack need be supplied to a line. In multiple switchboard practice, one of the jacks may act as an answering jack, the answering jaclcs, as is understood, being suitably distributed among thediil'erent sections of the switchboard, the multiple jacks being multi led to which grouping arrangement, or an other preferred grouping, is well understoo In the embodiment oi" the invention shown, the line relays 11 have their windings desir.- ably permanently included in extensions of the several sections of the switchoard,

the conductors 8 and-in connection with the common battery 12, the circuit of this battery desir-ably having one of its poles permanently connected with one side of each of the subscribers7 circuits through the relays 11 and the other sides of the su scribers circuits through the impedance device 13. When a subscriber removes his telephone, the line relay 11 becomes energized, whereby a signal through the line signal device 14 of the calling subscriber may be closed by way ci a line relay switch 15 and its alternate Contact 151.. The circuit of each line indi catoralso includes the armature switch 16 andP the normally engaged back contact 161 o' thc cut-oli relay 17 corresponding to the signal device 14. When a cut-off or line signal-efl'aoing relay 17 is energized, the circuit of the corresponding line ole connected with the other signal is opened at 161, whereby the line sig- When a plug, such as plug 191s inserted into a jack, the tip 20 of the plug en ages a jack sprin 21 ofthe jack into which t e plug 1s inserte which jack spring lis connected with the back contacts -of the armature switches 15 and 1S, and, by reason oi' its connection with the blick contact, the armature switch 18 is included in the local circuit that isinitially established Jier the cut-cti` relayl'?,

this local circuit, as now established, being traceable from the upper pole of battery 12 to the armature switch 15, t e alternate contact 152 of the latter armature switch, the winding oi' relay 17, which is preferably of large resistance, say one thousand ohms, the armature switch 18, its 'normal contact, the jack spring 2l, the tip 2() of the engaging plug, the conductor including the clearingout or supervisory signal 22 (which signal is n ot operated, for the circ-uit now being traced is only momentarily established), the body contact 23l of the plug 19, thence to the remaining terminal or' the battery 12 by way of the impedance coil 13. If the plug 23 were the lug inserted, the circuit traced would be lsinn ar. When circuit is thus closed through a cut-o relay, the armature switch 18 is attracted, thereby interrupting this circuit, but inasmuch as this armature switch is attracted very quickly, it has time to engage its alternate contact 24 before the cut-off relay is deenergized, whereupon a second local circuit is established to maintain the cut-olip relay energized until the corresponding switch-hook or switching device is operated at the corre spending sub-station to effect an opening of t is circuit of the cut-off relay. This second local circuit for the cut-off relay may be traced from the upper pole of the battery 12, through the armature switch 15, the contact 152 engaging said armature switch, the winding of the cut-ofi" relay 17, the armature switch 18, the alternate contact 24, to the remaining terminal of the battery 12. It will be seen that this circuit last traced includes none of the a paratus under the operators oit relay is broken at 152`without the aid of the operator. By making the cut-ofi relay of high resistance, a minimum quantity of current is required to maintain its energizetionduring an established connection. As hitherto stated, either plug 19 or 23 has siinilar effect upon the cut-olf relay circuits correspending to the jacks with which said plugs are engaged, and the parts upon the right hand of the drawing that are similar tothe parts upon the left hand of the drawing are given similar characters of reference, with the exception that thesupervisory signal u )on the right hand of the cord circuit is mar ed 25. The clearingmut or supervisor signals 22,25 are desirably in the form of sma l incandescent lamps, though l do not wish to be limited to the character ori signaling devices employed as clearing-out or supervisory signals, and while I prefer two signals for each cord circuit one corresponding to the calling subscriber and the other corresponding to the called subscriber-l do not wish to be limited to the cuit has the signal included therein normally disconnected from battery, that is, it is disconnected from battery while the cord circuit is out of service, which is another feature of my invention. Battery is only connected with these clearing-out or supervisory signals when the cord circuit is in use. In the embodiment of the invention shown, theisupervisory signal circuits include each thelltip of a plug, the non-talking strand of the cord circuit connected witheaid ilug, the talking strand connected with ithtlliody contact 231 and the supervisory signal eonnected between said strands, the bod'Y contact or thimble of the engaged jack, the inipedance 13, the battery 12, the armature switch 15, the back contact of said armature switch (for the clearing-out or'supervisory si nal circuits are only closed` when the line re ays are denergized, back to the tip 20. It is apparent that the supervisory signal circuits when closed are opened u on the withdrawal of the corresponding p ugs, by reason of the se aration of the e eiiients 2U, 21. Either of t e plugs 19, 23, in multiple switch-board practice, may, in accordance nected with the tip 20 o' the plug 19, while the other half of the pr mary is connected with the tip 20 of the p ug 23 when the operators key is operate( to cut lier telephone into circuit, the half ofthe primary t iat is Vconnected with the tip 20 oi plug 10 being included in tbe test circuit when the plug 19 is used as a testing plug, while the other half .of the primary is included in thc test circuit when the plug 23 is used as a-tcsting plug. Assuming that either plug is used as a test plug, and assuming that ajack that is being tested is associated with the line in a jack of which a plug is elsewhere inserted, the. test circuit will he as follows: From the ground at 27, through one-hall or the other of the primary of the operators testing 0utiit, according to the plug that is being used, to the tip of the'testingplug, the thimble 9 of the tested jack, the body contact 231 of the plug inserted in another jack belonging essere i ab to the group that contains the jack being cord circuit conductors including the su ertested, the supervisinfv signal corresponding visory or disconnect signals, which cont ucto the other plug, to the tip of said other tors are normally disconnected from .said lug, ,the spring contact 21 engaged hy the battery,-line relaysfor the telephone lm es, atter tip, the armature switch 15 and its and an armature switch foreach ofhsaidline 70 normal coiitact` iiow assuming that the line relays, each controlling the continuity of the is open at the sub-station), to one pole of the corresponding disconnect signal circuit. battery 12', through said battery, to ground, 2. A. telephone exchange system includinor thence back to the ground at 27. If the line telephone lines extendinr to an exchange an l isclosed at the substation, the test circuit there provided with jac s, cord circuits for 75 will be traced from the ground at 27, through uniting lines in conversation,'disconnect siga haii of the .primary '28 of the operatorsI nais associated with the cordcircuits, battery vtesting outlit, the tip ot the testing plug, for effecting the operation of the disconnect the thiinblc Si of the jack being, tested, signals and normally disconnected from the i5 through thc sub-station, the line relay 1l, cord circuit, circuits for the disconnect sigso Jthrough the battery 12, to ground. The nals,-including said battery, jack contacts secondary 254' is included in circuit with the with which said battery is normally connectoperators receiver, the testing current being ed, plug contacts for engaging said 'ack coninduced in the operiitors receiver circuit. tacts, and cord circuit conductors including 20 It will bc seen that the testing battery curthe supervisory or disconnect signals, which 85 rent is normally removed from the idle cord conductors are normally disconnected from circuits by my improved circuit arraiige-A said battery,-line relays 'cr the telephone ment. lines, and an armature switch for each of Another feature of my invention resides in said line relays, each controlling the conti- .'25 thc intcrchangcability of the plugs of each nuity of the corresponding disconnect signal 90 cord circuit, as l may use either plug es a circuit.

connectii'ig and testing plug and either plug 3. A telephone exchange system includin as an answering plug. To this end, l assotelephone lines extending to an exchange ani. ciatc a ringing key 29 with each of the plugs, there provided with jacks, cord circuits for Sfso that the ringing generator 30 may be uniting lines in conversation, disconnect sig- 95 thrown into connection with either of the nais associated with the cord circuits, battery plugs. llach of the ringing keys 29 breaks for effecting the operation of thevdisconnect the cord circuit when it is operated, so that signals and normally disconnected fronithe the culling generator 30 is limited to circuit cord circuits, circuits for the disconnect sig- 85 relation with but oneof the plugs. The adnals,-includin f said battery, jack contacts, 100

vai'itagc oi' this feature of my invention rc' plug contacts Aor engaging said jack consides in thc fact that if a called subscriber tacts, and cord circuit conductors including should become a calling subscriber before the supervisory or disconnect signals. which the plug is removed from his jack, the mate conduct( rs are normally disconnected from '40 to said plug may be usedin testing the said batteiy,-line relays for the telephone 105 newly called for subscriber, and il said sublines, and an armature switch for each of said scribcrs liuc bc i'ound idle, said latter plug line relays, each controlling the continuity of may bc inserted into the newly called subthe/corres onding disconnect signal circuit.

scribcrs ,nick -and said newly called sub- 4. A te cphone exchange system including scribcr muy be rung by the operation of the telephone lines extendin rto an exchange and 110 y corresponding ringing key. there providedwith jzic s, cord circuits for lt is obvious that changes may readily be uniting telephone lines, line signal mcclianniadc in thc pref erred enibodiinentiof my in ism, cut-ofi' or line signal-effacing relays nor-V vention, wit iout departing from the spirit mally in circuit connection Withvjacks of the thcrcol', and l doiiot, therefore, wish to bc corresponding line, said cut-oil' relays in es- 115 limited to the precise constructions 'and artablishing their alternative circuits opening rangcincnts shown, but, their previously established circuits, circuit lluviiig thus described my invention, l connections for the cord circuit plugs, Wherecluini as nciv and desire to secure by liettersby circuits through said cut-oil` relays may be Patciitr-A i momentarilyclosed, alternative circuits for 120 l. telephone exchange system including said cut-oil relays established thereby, and telephone lincscxtcnding to an exchange and line relays entering into the control of the there provided with jacks, cord circuits for latter circuits. i uniting liiics in conversation, disconnect sig- 5. A telephone exchange system includin f nels associated with thc cord circuits, battery telephone lines extending to an exchange an 125 i'or cfl'ccting thc operation oi the disconnect there provided with ljacks, cord circuits for signals and normally disconnected from the uniting telephone lines, line signalinechancord circuits, circuits for the disconnect sig'- ism, cut/ofi or line signal-eilacing relays, said nels, including said jack contacts, plug con cut-cti relays in establishing their alternative tacts for enga 7ing said jack contacts, and l circuits opening their previouslyestablished 130 essere circuits, circuit connections for the cord cirl entering into'tlie controlof the lattercircuit plugs, whereby circuits through said cutoff relays may be rnomentaril closed, alternative circuits for said cut-o relays established thereby, and line `relays entering into the control of the latter circuits.

6. A telephone exchange system including telephone lines extending to an exchange and there provided with jacks, cord circuits for uniting telephone lines, line signal mechanism, cut-oii' or line signal-efacing relays normally in circuit connection with jacks of the corresponding lines, circuit connections for the cord circuit lu s, whereby circuits through said cut-o? re ays may be momentarily closed, alternative circuits for said cutoiT relays established thereby, line relays entering into the control of 'the latter circuits, and a battery for energizing said cut-ofi' rela s, said batter being normally disconnecte from the cor' circuits.

7. A tele hone exchange system'including telephone ines extending to an exchange and there provided with jacks, cord circuits for unitingtelephone lines, line signal mechanism, cut-oli' or line signal-eiiacing. relays,

` circuit connections for the cord circuit plugs,

whereby circuits through said cut-off relays may be momentarily closed, alternative circuits for said cut-off relays established thereby, line relays entering into the control of the latter circuits, and a battery for energizing said cut-oli relays, said battery being normally disconnected from the cord circuits.

8. A tele. )hone exchange systeml including telephone lines extending to an exchange and there provided with jacks, cord circuits for uniting telephone-lines, line signal mechanism, cut-oilv or line signal-eifacing relays normally in circuit connection with jacks of the corresponding line, said cut-oil` relays in establishing their alternativ(` circuits opening their previously established cil'- cuits, circuit connections for the cord circuit plugs, whereby circuits through said cut-oil' relays may bc momentarily closed, alternative circuits for said cut-oil' relays established thereby, line relays entering into the control of the latter circuits, and a battery for energizing said cut-oil' relays, said battery being normally disconnected from the cord circuits.

t). A telephone exchange system including telephone lincs extend-ing to an exchange .and there provided with jacks, cord circuits l'or uniting telephone lines, line signal mechanism, cut-ofi` or line signal eil'acing relays, saidI cut-o? relays in establishing their alternative circuits opening their previously established circuits, circuit connections for thel cord circuit plugs, whereby circuits through said cut-oill relays may be momentarily closed, alternative circuits lor said cul-oil relays established thereby, line relays cuits, and a battery for energizing said cutof relays, said battery being normally dis- .connected from the cord circuits.

i0. A telephone exchange system including telephone lines extending to an exchange and there provided, with jacks, cord circuits for uniting telephone lines, cut-or' or line sigiial-effacing relays' normally in circuit connection with jacks of the corresponding line, said cut-oft relays in establishing their alternative circuits opening their previously stablished circuits, circuit connections for the cord. circuit plugs, whereby circuits through said cut-0 relays may be momentarily closed, alternative circuits for said cut-oil relays establishedthereby, line relays entering into the control of the latter circuits, line signal devices, and circuits' therefor establishable by the line relays and breakable by the cut-olf relays.

11. A telephone exchange system including telephone lines exten/din to an exchange and there provided with jac s, cord circuits for uniting'telephone lines, cut-oilor line signal-elacing relays, said cut-ofi relays in establishing `their alternative circuits opening their previously established circuits, circuit connections for the cord circuit nlugs, whereby circuits through said cut-oil` relays may b e momentarily closed, alternative circuits tor said cut-ofi' relays established thereby, line relays entering into the control of the latter circuits, line signal derices, and circuits therefor establishable by the line relays and breakable by the cut-onqv relays.

i2. A telephone exchange system includcuits t'or said cut-oil' relays established thereby, line relays entering into the control 0i the latter circuits, a battery for energizing said cut-oil relays, said batter being normally disconnected from the cor( circuits, line si nel devices, and circuits thereforestablishab e by theI line relays and breakable by the cutoll relays.

i3: A telephone exchange system including telephone lines extending to an exchange and there provided with jacks, cord circuits for uniting telephone lines, cut-ofi oriine signnl-cihuing relays, circuit connections for thc cord circuit lugs, whereby circuits through said cut-o relays may be momentarily closed, alternative circuits 'for said outol' relays established thereby, line relays entering into the control 'oi the latter circuits, a battery for energizing said cut-oli relays, said battery being normally disconnected teryV for energizing said essere' from the cord circuits,A line s' al detfices;4

l and circuits therefor establishab e by the line l relays and breakable by the cut-0E relays.

14. A telephone exchange system including telephone lines extendin to an exchange 'and there provided with jac s; cord circuits for uniting tele hone lines, cut-oli 'or line signal-efacin re ays normally in circuit con- 15. Atelephone exchangel systemincluding telephonelin'es extending to an exchange and` there provided with jacks, cord circuits foruniting telephone lines, cut-0H or line signal-eifacin mg their previously established circuits, circuit connections ior the cord circuit plugs, whereby circuits throu h said cut-off relays may be mornentarilyc used, alternative circuits or said cut-oli relays established there` by, line'relays entering into thecontrol of the letter circuits', a battery for ener i cut-off relays, said battery disconnected from the cor nal der fices, and circuits ableb the cnt o relays 'being normally circuits, line sitherefor establis relays,' said cut-'oi relays 'in' 'establishing t eir alternative circuits open-- said line relays and breakable bythe l. In witness whereof, ijibreuntc subscribe my 'name 1906. A

v Wit'desses:

' Linen ysrsoir I lELMERVv n.. oestrin.

this 26th dayvoflfsepteinberli. D.,V 

